Burning Mac software question

I need to burn some Mac software for a friend I use a Microsoft pc here is what I need to know...

Is a xxxxxx.dmg file the same as a xxxxx.iso
How do I check to see if a xxxx.dmg file is bootable
What software can I use on a pc to burn xxxxx.dmg files
And how many discs are there for both Leopard and snow leopard